More than 60 years worth of reported UFO sightings over Stonehenge and Parliament were released Friday in 4,300 pages of data from Britain's Ministry of Defense, who explained why its UFO division closed more than three years ago.

"That really did put a strain on the resources that the MoD had committed to this subject, and really led up to their decision to finally pull the plug on Britain's X-Files, simply because they just didn't have the resources to investigate these sightings, or to look at them in any detail," Clarke said in the video. "So they just tended to be filed away."

In January 2009, photographs showing an odd shape in the sky over Stonehenge were sent to the ministry, along with an emailed note. The ministry responded that it doesn't seek to identify such UFO sightings "unless there is evidence of a potential threat to the United Kingdom," NBC News reported.

Chasing down every sighting would be a waste of time and money, the ministry said. A witness who reported seeing "a craft that had green, red and white lights" over the Houses of Parliament in February 2008 received a similar ministry reply.

Some of the mysteries are easily explained. In June 2008, a police helicopter crew reported a pack of small, rotating objects in the sky, but the ministry concluded that they were Chinese lanterns floating up from a nearby wedding. A tale in January 2009 had witnesses who reported spheres of flashing lights that turned out to be fireworks set off in celebration of an 80th birthday party.

"We have now come to the end of this program of release for the UFO files, and it is often said about UFOs that 'the truth is out there,'" Clarke said in the video. "In my opinion, the truth is actually in here, in these files."